Method __init__

Day01-15/Day09/rational.py:16–21

(self, num, den=1)

class Rational(object):

	def __init__(self, num, den=1):
		if den == 0:
			raise ValueError('分母不能为0')
		self._num = num
		self._den = den
		self.normalize()

	def simplify(self):
		x = abs(self._num)